The invention relates to a valve for regulating the passage of a fluid through pipes, in particular ventilation pipes and/or rinsing pipes of large diameter, which pipes are to be connected to safety containers for nuclear reactors.
For the continuous ventilation of safety containers for nuclear reactors, ventilation pipes of large diameter are arranged at the safety container which pipes are provided with shutoff valves for safety reasons, so that the safety container can be immediately gas-tightly sealed against the outside upon occurrence of complications. Such shutoff valves are also provided in the rinsing line through which the safety container is cleaned after such a disturbance took place.
Until now, shutoff flaps have been provided in ventilation pipes and in rinsing pipes of the safety container. For actuation of the flap disk, a lever gearing has been used consisting of several toggle joints, so that the flap disk is first pivoted in a position plane-parallel with the housing seat until shortly before the shutoff position is attained, and thereafter is pressed on the housing seat in essentially axial direction. Through this plane-parallel engagement of the flap disk into the housing seat, the required tightness in the flap seat is achieved despite the large diameter of the ventilation and rinsing pipes, but such a lever gearing is rather complicated and cumbersome. Moreover, the drive shaft which must provide the driving moment during the opening and the braking moment during the closing has to be guided outwardly through the housing wall, so that the shutoff device becomes very cumbersome, especially when considering the required quality of the sealing in nuclear reactors. A further disadvantage resides in the fact that the entire shutoff flap must be disassembled from the pipeline in order to inspect the movable flap part and the housing seat during the inspections periodically occurring in nuclear power stations.